Polyelectrolyte membranes (PEM) are nanostructured materials widely applied in many fields, including chlor-alkali technologies, water purification, proton exchange membranes for fuel cells, sensors, and personal care products. The unique transport properties of PEM are due to their nanostructure: PEM contain both hydrophobic fragments and hydrophilic groups that dissociate in water. Therefore hydrated PEM undergo a nanoscale segregation into hydrophilic (aqueous) and hydrophobic (organic) subphases. Understanding the structure-property relationships in PEM is a key to creating new membranes and improving their characteristics.

The presentation describes recent efforts in predicting structure and transport in PEM using dissipative particle dynamics (DPD). DPD is a mesoscale modeling technique, in which a system is presented as a collection of “beads” interacting with each other via soft short-range potentials. We show that with proper parameterization, DPD can predict the structure and dynamics in PEM on qualitative and even quantitative level. The presentation focuses on two different classes of PEM:

(1) Carbopol gel, a polyacrylic polymer material applied in personal care products. With DPD, we explore the interactions between Carbopol and added sur-facetants, both non-ionic and ionic in an effort to elucidate the influence of surfactant load to the material properties.

(2) Proton-exchange PEM for fuel cells membranes. We focus on relationships between the chemical composition of the membrane, hydration and water/proton mobility. To explore this system, we intro-duce a novel approach that allows incorporation of reactive equilibria directly into DPD simulation.

Special attention is paid to model parameterization strategies, especially to those that make DPD a predictive tool available to non-experts in the field of mesoscale modeling.

SPEAKER INTRODUCTION:

Dr. Aleksey Vishnyakov is an associate research professor at Rutgers University (NJ, USA), Department of Chemical and Biochemical Engineering. His research efforts are focused on the development of new molecular and mesoscale modeling techniques, particularly targeting applications to nanostructured materials: porous solids, thin films and polyelectrolyte membranes..